Quilted fabric and method

ABSTRACT

A quilted fabric produced by increasing the number of courses per unit length so as to be at least eighty for each ten centimeters and based upon the tension of the reinforcing thread, the stitch formation, the filling coefficient and other factors so forming the shape of the loop so that it has a front loop portion which is substantially flat and a back loop portion which is substantially semi-circular.

United States Patent Horeni et al.

Sept. 9, 1975 QUILTED FABRIC AND METHOD Inventors: Bohumir Horeni, Hlavni; Vladimir Zid, Libcrec; Bohuslav Neckar. Liherec; Jan Prochazka, Lihcrec, all

of Czechoslovakia Assignee: Statni vyzkumny ustav textilni,

Liberec. Czechoslovakia Filed: July 9, [973 App]. No.: 377,408

Related US. Application Data Continuation-impart of Scr. No {Mi/J94, Aug. 4,

l969 abandoned.

Foreign Application Priority Data Aug. 6, W68 Czechoslovakia 5696-72 U.S. Cl 66/193; ll2/4l2 Int. Cl D04b 23/10 Field of Search 66 192, l93. 85 A;

[56] References Cited UNITED STATES PATENTS 2.158906 5/l939 Ellis two/l9} X 3.323.l89 6/l967 Hayashi (vb/I93 X FOREIGN PATENTS OR APPLICATIONS 1.043.772 1 H1958 Germany [12/412 512.488 9/1939 United Kingdom .0 two/I92 Primary liruminer-Wm. Carter Reynolds [57] ABSTRACT A quilted fabric produced by increasing the number of courses per unit length so as to be at least eighty for each ten centimeters and based upon the tension of UIL reinforcing thread the stitch formation the filling coefficient and other factors so forming the shape of the loop so that it has a front loop portion which is substantially flat and a hack loop portion which is substantially semi-circular.

10 Claims, 22 Drawing Figures PATENTEU SEP 9 I9 5 sum 1 or 7 PRIOR ART rd PRIOR ART PATENTEU SEP 9 I975 sum 3 Bf 7 PATENTED SEP 91975 saw u n; 7

PATENTEU SEP" 9191s sum 7 o 1 QUILTED FABRIC AND METHOD RELATED CASE This application is a continuation-in-part of our copending application Ser. No. 847,194. filed Aug. 4. 1969, now abandoned, to which reference is made for any disclosure. amplifying. extending or supplementing the contents hereof and such disclosure is incorporated herein as if more fully set forth here.

BACKGROUND OF THE INVENTION The present invention relates to the quilting of a fleece, batt or fibrous webbing and more particularly to the production of improved quilted fabrics.

Stitch-bonded or knitted quilt fabrics of natural or synthetic fibers are well known and extensively used. In such fabrics, a web of fibrous material, either as fleece, sandwich batt, or monofilament yarn is reinforced by one or more binding networks of warp stitching to produce a fabric having a plurality of symmetrical or uniform tufts filled with fibrous material. The most comrnon networks used are single warp or chain stitch, tri' cot stitch or combinations thereof in a network, not exceeding 6O wales per cm and 80 courses per 10 cm.

It has been found that conventionally stitched quilted fabrics have poor structural properties exhibiting a severe lack of tensile strength and slippage of the fiber at the binding points. As a result, the slightest tension causes a permanent deformation of the tuft, which during wear allows bulging of the fabric at stress and flex points. such as knees and elbows. low resistance to abrasion; tendency to pill and. in pile or raised fabric. to shed. conventionally stitched quilted fabrics also exhibit poor ability to anchor or clamp the fiber bundles, within the loop, resulting in extremely low resistance to transverse tension and actual loss of fibers from the fill. These situations appear to arise'or'be caused either by an insufficient number of c0urses,the improper shaping of the tuft loop. or by the application of insufficient tension on the thread. producing as a consequence a low co-efficient of tuft filling which may be defined as the ratio between the sum of fiber cross section areas in a stitch loop and the total area confined by the stitch loop. Consequently. the fabric produced by conventional methods is limited to such uses as insulating material, textile laminate backings and decorative fabrics. all of which are subject to little, if any. exposed wear.

It is the object of the present invention to provide quilted fabrics in which the disadvantages enumerated above are non-existent.

It is another object of this invention to provide quilted fabrics having such degree of quality as to be readily usable as outwear clothing and in other applications where strength, form and shape are required.

It is a specific object of the invention to provide a quilted fabric wherein the co-efficient of tuft filling is increased, the loop shape stabilized and the stitch bonding point strengthened.

According to the present invention a quilted fabric is produced by increasing the number of courses, the thread tension, and the shape of the loop in a predetermined and defined manner dependent upon its weight. specific gravity and the thickness of the fibrous web fillv It has been found that quilted fabric made according to the present invention will have a considerably higher strength. a greatly suppressed tendency to bulge as well as a higher fiber anchoring than conventional fabrics.

Spontaneous fiber shedding or pilling during wear will also be markedly reduced even if the fabric is raised or pilled. The fabric produced by the present invention rivals more common fabrics. such as sateens, regular knits, etc. and may be used in such new applications as in outerwear. underwear, furnishings and beddings as well as in a variety of industrial uses. Above all. the fabric is simple to produce, having a low production cost and high production rate on readily available conventional machines.

BRIEF DESCRIPTION OF THE DRAWINGS The above objects and advantages, as well as others, together with a detailed description of the invention, will be seen from the following description taken with regard to the annexed drawings in which:

FIG. I is a schematic representation along a longitudinal section showing the loop formation and tuft structure of successive courses in a single wale of conventionally stitched fabrics, while the same remain on the knitting machine;

FIG. 2 is a view similar to FIG. 1 showing the fabric of FIG. 1 in relaxed condition and removed from the knitting machine;

FIG. 3 is a view similar to that of FIG. 1 wherein a stable loop is formed in accordance with the present invention;

FIG. 4 is a view similar to that of FIG. 3 showing a modified fabric according to the present invention;

FIG. 5 is a perspective view of a portion of a fabric of the type shown in FIGS. 1 and 2;

FIG. 6 is a perspective view similar to FIG. 5 showing a portion of a fabric of the type shown in FIG. 4',

FIG. 7 is a perspective view of fabric made with a batting interior in accordance with the present invention;

FIG. 8 is a view similar to that in FIG. 7 showing the application of a combined chain stitch and tricot stitch network;

FIGS. 9a-9c show schematic views of a needle stitch mechanism employed to provide the present invention;

FIG. 10 is a schematic view of a needle stitch mechanism and quilting machine elements employed to provide the fabric of this invention;

FIG. 11 is a graph of the course of the coefficient of stitch loop filling;

FIG. 12 is a graph of the course of the coefficient of stitch loop filling when transverse deformation of fiber profiles arises, curve a and the corrected curve b;

FIG. 13 is an illustration of the loop stitch of the invention showing that the upper side of the loop is constituted by two yarn ends with the force 2F acting on the upper part of the loop and the lower side of the loop constituted by one yarn end with the force F acting thereon;

FIG. 14 is an illustration of the stitch loop shape below the stability limit;

FIG. 15 is a diagrammatic illustration of the formula 6,. G/N for determining the fiber weight in a single course;

FIG. 16 is a diagrammatic illustration of the stitch loop shape at the stability limit when the lower loop stitch arch is semi-circular;

FIG. 17 is a diagrammatic illustration of the stitch loop shape above the stability limit;

FIG. 18 is a diagrammatic illustration of the formula, D=( l/N) (DJCOSib) where the loop stitch is below the stability limit;

FIG. 19 is a diagrammatic illustration of the formula, D l/N) D,. for determining the knit course number for stitch loops at and above the stability limit; and

FIGS. 20 (a) (b) are diagrammatic illustrations for determining the length of the chain stitch yarn.

DESCRIPTION OF PREFERRED EMEODlMENTS Turning to FlGS. l, 2 and 5, which, it will be recalled. show a conventionally formed fabric, there is seen a plurality of coursewise tufts T formed of fibrous web W, reinforced by a plurality of simple chain stitch thread 1 bound respectively at points A, all lying along a common axis. Each of the tufts T, of this fabric, are of an elongated eliptical cross section; that is, the upper thread portion L,, is substantially equal to the lower thread portion L and the cross sectional surface P of the ellipse has substantially equal upper and lower portions 2 and 3 respectively. The fabric even in its relaxed state, as seen in FIG. 2, is not significantly altered, in its shape, although each tuft T does become somewhat more round having a total surface P, somewhat larger than its original surface P as seen in FIG. 1. The loop portion L, and L as well as the surface portions 2 and 3, nevertheless remain substantially equal to each other. Such an elliptical body is highly elastic since any pull on its fabric will cause it to elongate and the loops L, and L to straighten along the axis 0. Thus, as tension is applied to the fabric the loops readily change shape causing the binding points A to loosen, shift position and permit the web filling to be dislodged. It will also be observed that the filling coefi'icient m of the conventionally formed fabric (FIG. 5) is extremely poor since the ratio between the sum of fiber crosssection areas in a stitch loop and the total area confined by the stitch loop is small, consequently the force F, necessary to pull a fiber from the tuft is minimal and that transverse deformation is quite high. The end result of course is a fabric which has the disadvantages enumerated in the introduction hereto.

We have found that a stable quilted fabric is formed by establishing the number of courses based upon certain of the processing parameters. as for example, those relating to the stitch formation, number of wales and thread tension. As will be described in greater detail hereinafter, changes or modifications can be made so that the process may be adapted to any conventional warp quilting machine, as for example, that shown in US. Pat. No. 3,310,964 issued Mar. 28, 1967 to E. Peschl et al.

These parameters have been embodied in a formula wherein any fibrous web having a weight of up to 600 grams/square meter can be reinforced with a network of threads in any warp stitch construction wherein the network comprised a number of courses per each cm at least equal to N, N being determined by the equation wherein G weight in g/sq.m of the fibrous web to be pro cessed T binding thread titre in denier y specific gravity in g/cu. cm of the fibers in the web in the constant equalling 0.40 representing the filling coefficient of the material a the constant which with the fibrous web weight up to 200 g/sq.m equals zero while with the fibrous webs of weight range of from 200 to 600 g/sq.m. is determined by the equation and represents machine operating factors such as thread tension, winding tension etc.

in order to appreciate the significance and the derivation of the above formula the following basic principles of binding yarn feeding and tension are set forth and the derivation of the formula per se is set out.

Within each operating cycle of the stich-bonding process as shown in schematic FIGS. 90, 9b and 90, a certain predetermined binding yarn length is supplied to the stitch forming organs, or in other words, the supplied yarn length in any given case is the same or constant within each operating cycle. This is achieved by the fact that within each operating cycle the yarn package from which the binding yarn is wound off turns by a predetermined angle, thus dispensing the aforesaid constant binding yarn length.

Referring now more particularly to F 1G. 10, the constant binding yarn supply proceeds as follows:

The rotation of the warp beam 31, that is, the binding yarn package, is controlled by a let-ofi" motion 32 comprising a plurality of gears designed to transmit the movement from the main machine shaft up to the warp beam. The rotational movement is divided in the let-off motion into two components which, if added or subtracted in a differential, will give the resulting continuously controllable warp beam rotation rate.

The control of the differential gear performance is based upon the position of a tension controlling rod 33 and transmitted via a crank lever 34 and a connecting rod 35 to the let-off motion 32.

Thus, the position of the tension controlling rod 33 affects the yarn feeding rate.

For example, with a fully wound warp beam, the tension controlling rod is in the position 33' so that the beam rotation will be slower than in position 33" wherein the warp beam is almost empty and will rotate at higher speed. Consequently, in this manner in the two cases mentioned the respective lengths of let-off warp or binding yarns remain the same.

Apart from the aforementioned constant yarn length, the tension controlling rod makes it possible to take off, within each operating cycle, a necessary surplus length of binding yarn, which length, after the cycle has been closed, is retracted or taken up again by the action of the tension controlling rod.

Such a pulsating or oscillating yarn feeding system operates as follows:

In the yarn tension controlling mechanism described above which comprises the tension controlling rod 33, crank lever 34 and connecting rod 35, a certain play is provided, enabling the tension controlling rod 33 to oscillate within limits during the stitch loop formation and to act at the same time as a consumed yarn length compensator. The play is denoted in FIG. 10 by referencc symbol a is relatively small and cannot influence the position of the differential of the yarn feeding rate.

The entire aforementioned process of both constant and oscillating feeding within the stitch-bonding cycle takes place under a preadjusted binding yarn tension.

This tension is adjusted as follows:

On a shaft 36 carrying the tension controlling rod 33 and the crank lever 34 there is provided a helically wound flat spring (not shown) of which one end is attached to the shaft 36 while the other bears upon a stationary abutment arranged on the machine sidewall.

The spring end portion is not fixedly attached to the shaft 36 but rather adjustably by means of an adjusting ring (not shown) so that the torsion of the spring can be reduced or, on the contrary, increased, thereby making it possible to control the entire warp yarn ten sion.

Coefficient of Stitch Loop Filling From a purely theoretical standpoint the dependency of the stitch loop filling coefficient m upon the yarn tension F cannot be justified since m m(F) where the function m(F) increases together with increasing quantity F. Since the filling coefficient m, for principally physical reasons, has to vary within interval on of (0 I). m 0 corresponds to F O and m I theoretically corresponding to the theoretical quantity F a. Moreover, since the function m(F) has, for principally physical reasons, within the entire interval P (0,-+0:) a positive derivative, the function m(F) can be schematically plotted as in FIG. 11.

No substantial physical reasons can be found for the above relation being discontinuous in the first derivative, or for the understanding of inflexion points therein.

The relation m(F) shown in FIG. 11 holds until a transverse deformation of fiber profiles occurs.

The curve m(F) involving this deformation factor has a different course, particularly for higher F quantities, as shown in FIG. 12 by a and where the corrected curve is indicated by 12.

No substantial physical reasons exist for which the relation might be considered as discontinuous in the first derivative, and for which it might involve an inflexion point.

lt is to be noted that the two curves have a converging limit for F* m towards m I but that the corrected curve b will acquire linear course much sooner, since except for the lowest values F, the second derivative is lower.

From the viewpoint of practical determination of the function m(F), this fact means that a relatively broad interval (X, Y) of the force F the relation can be ex pressed with sufficient technical preciseness as m( F) =1: m const.

The aforementioned expected facts have been fully proven by experimental research work.

In this experimental work, a plurality of webs of various orientation and specific weight were stitchbonded in varying knit-course densities and under varying warp yarn tensions under strict laboratory conditions. The filling coefficient was evaluated by conversion from experimentally found quantities, such as, besides others, the number of knit-courses in the taut fabric immediately behind the needles, and in appropriately treated released fabric.

It has been found that within the examined warp yarn tension interval which was kept during the experiment at many times higher and lower than that allowed by practical technological conditions, the filling COCffiCient of the fabric behind the needles is practically independent of the yarn tension. and web orientation.

Likewise, no influence of web weight on the quantity m was observed.

On the other hand, the filling coefficient m in released and treated fabrics is markedly dependent on the selected knit-course number, it being, in the case of a lower course number than disclosed in the above formula, always lower than the substantially constant cocfficient in the taut fabric just behind the needles.

In case of the disclosed course number and higher course numbers, no difference between the coefficients was found in practice.

in summary, it can be stated that:

a. the relation m m(F) is not pertinent from a purely theoretical viewpoint;

b. the course of the function m m(F), however, is within a practically used yarn tension interval, flat" and practically indistinguishable from the formula m m( F) where m equals a constant, it being understood that the experimentally examined yarn tension interval was both above and below the yarn tension interval employed',

c. the statement in paragraph (b) holds also for webs of various specific weights and orientations;

d. the filling coefficient found with all types of fabric behind the needles and with released and treated fabrics having the same and higher knit-course numbers than that disclosed in the above formula has varied within a narrow interval of about m 0.4.

Stitch Loop Geometry of Chain Stitch Structures Practical examination of stitch cross-section has proved that the stitch loop has not a circular but rather a substantially unsymmetrical eliptical configuration.

The stitch loop is constituted on the upperside by two yarn ends and on the underside by one yarn end as shown in FIG. 13.

Assuming that the interval tension of the binding threads is the same in all regions, then the force 2F acts in the upper part of the stitch loop, whereas in the lower part thereof only the force F acts.

The stitch loop shape below the stability limit is shown in FlG.l4.

There results from the mathematical calculation of the relations involved in FIG. 14 the following:

From the equilibrium of vertical components of forces acting at the point B, it may be deduced that 2F COSQ F COSllJ lf inserting the preceding relations into the last mentioned equation, the result is that LL 2 2R 2r where from Thus, the radius of curvature of the upper branch of the stitch loop (1) is double the radius of the lower stitch loop branch (2).

The filling coefficient m may be defined as a relation between the sum of fiber cross-section areas in a stitch loop (P,.) and the total area confined by the stitch loop (PC) so that It is to be understood that in order to find the filling coefficient m the aforementioned quantities have to be known.

If we insert for the weight of a unit web element (g/sq.cm) the symbol G and for the density of courses per unit length l cm)the symbol N. the fiber weight in a single course (6,) will result from the following relation (see FIG.

If P,. (sq.cm) is the total area confined by the stitch loop in a single course (FIG. 15) the specific weight of compressed web element in the loop can be calculated from the following formula If the specific weight of one cu.cm fiber mass (g/cu.cm) is replaced by the symbol 1/ then the sum of fiber cross section areas in a stitch loop (P,.) will result from the following relation After substitution in the foregoing equations we re ceive The loop stitch cross-section area 1% is derived as follows:

The segment area P bounded by the arch of radius R and by the line segment AB (i.e. the upper segment of the circle) is given by the following mathematical relation:

The segment area P, bounded by the arch of radius r and by the line segment AB (ie the lower segment of the circle) is analogously given by the relation Pr=F -w) From the foregoing equations for P and P the total area P of stitch loop is found to be the sum P P, or

l 2 Dr sin I]! l DRsin+ The stitch loop shape at the stability limit is a particular case of the general stitch loop shape wherein the center of a circle of radius r, ie the point S has descended into the point 0 and become identical therewith. ln this case the lower stitch loop arch becomes a semicircle as shown H0. 16.

For this particular case the following relation holds:

After substitution of the foregoing relations into the formula for the calculation of P it is seen that in regard to the stitch loop shape under the stability limit the following relations hold:

Thus, for instance, for ll! 20; cos Ll! 0.93969; are i];

and further sin ll! 0.34202 are (I) 1.082]; sin 4) 0.88295 After insertion of the aforesaid quantities into the equation for the determination of P,. the following formula is obtained The stitch loop shape above the stability limit (i.e. also a stable shape) is shown in FIG. 17. A

The total stitch loop area P,. is given in this case by the relation:

P D 0.483 Da if putting a a D the following formula will be obtained:

P D (0483 a After substitution of the last mentioned formula into the equation for the calculation of knit-course number N, that is the following fomula is obtained:

Further for D below the stability limit the following relation shown in FIG. 18 holds:

cos d:

Since, however, it is necessary to determine the knitcourse number N for the stitch loops at the stability limit, D can be calculated from the relation:

as shown in FIG. 19 and wherein D,- binding yarn diameter. The foregoing formula is to be substituted into the equation for determining the quantity N.

After substitution and simplification the following formula results:

After inserting an auxiliary quantity A (0.483 a m 8 there is obtained for the solution of the foregoing quadratic equation the following relation:

After inserting another auxiliary quantity B G/ZA- 1),. the following formula is obtained:

Since the negative sign only has the physical sense it holds further that I 2 I). l 1),.

wherein B G/ZAD and as A (0.483 a m 7 so that (0.483 a) my Further for the calculation of the binding yarn diameter the following relations hold:

After inserting the above quantities D into the foregoing equations for N and B, respectively, the following formula is obtained:

8946 l5|.79 n VT in which T i 0.433 a) m Since in practice the weight of the stitch-bonded web is expressed mostly as weight of l sq.meter in grams ((5 [g.m and the knit-course number N per l0 em (1 dm), the following final formula is obtained 7589.46 151 79 N ldm"] \7 100B 1* 1+ H in which 2.880 um H ls l which formula is the same as set forth above and wherein G weight of l sq.metcr of the stitch-bonded web in grams T titer of the binding yarn in denier 'y= specific gravity of the fibrous layer in g/cu.cm. m filling coefficient which equals 0.4 a stability coefficient which the fibrous layer weight up to 200 g/m is zero so that it is fully sufficient to make stable fabrics up to aforementioned fibrous layer weight on the stability limit. and which for fibrous layers within the weight range of from 200 to 600 g/sq.m is given by the formula Thus in the stitch-bonded fabric below or under the stability limit, when removed from the machine and appropriately treated. is then allowed to relax, m is rendered lower tha 0.4 and consequently the use value of the respective fabric is unfavorably affected.

This release is enabled by the length of the chain stitch yarn, as hereinafter explained.

The length of the chain stitch yarn can be derived from FIGS. 14 to 20, and particularly from FIGS. I9 to 20. For this length the relationship is Rua. (g a) This length, however, should be slightly increased, since the binding yarn surrounds in the point B (see FIGS. 13 and I4) two binding yarns, as can be seen in FIG. 20.

In practice, two modes of encircling are possible, i.e. 200 or b. Thus, it is necessary to add to the length 1 either 11D,. or ('n'D,. D,.). Since the respective encircling mode cannot be predetermined, an average quantity for 1,. has to be introduced into the formula, such quantity equalling Thus, the total binding yarn length necessary for the chain stitch loop results from the following relation To determine the stitch loop length for the stitch at the stability limit there is obtained for l the following relation:

l= 3.67 D 6.26 D

d 62 and thus are d) 1.082; R 1.063 D d; 20 and thus are d; 0.349: r D/l.88

there is obtained for I the following formula:

Finally, to determine the stitch loop length for the stitch above the stability limit there is obtained for I the following formula:

The fabric release, however, cannot occur with fabric on stability limit and with fabrics above stability limit either. Nevertheless the manufacture of fabrics above stability limit is not recommended, since the increased knit-course number unfavorably influences the machine productivity.

When multi-warp stitch constructions are used, e.g., with n (being more than one) warps containing different denier yarns, the total denier will be calculated from the equation While the lowest course density obtaining the required wear properties, as discussed above, will, of course, result from the maximized combination of the materials used and from their determining properties, it is believed that the greatest number of courses N should not, in practice, exceed 300 per 10 cm.

Employing the above formulation, novel quilted fabrics exhibiting enhanced wear qualities are obtained. Two such fabrics, similar to each other, are shown in FIGS. 3, 4 and 6 wherein the fabric is reinforced with a thread I bound at points A lying along the common axis a in which the upper loop portion L is considerably shorter than the lower loop portion L The fabric shown in FIGS. 4 and 6 differ from that shown in FIG. 3 in that the loop binding points A are vertically elongated, giving it a somewhat longer inner loop.

The fabric thus produced provides a lower loop portion L substantially semi-circular in cross section and an upper loop portion L having a more or less substantially flat contour. The cross-sectional surface or area P is also considerably larger than the cross-sectional surface or area P As will be obvious, a by any pull along axis a will cause only limited movement of the loops because the upper loop portion L defines the extent of such movement. The tuft loop can only be elongated so far as the upper b op protion L can be made to coincide with the axis a and since it is already substantially flat, movement is very small. Consequently, virtually no significant loosening of the loops at the binding points A, shifting of the threads or dislodging of web filling occurs.

Diagrammatic comparison of the improvement in the filling coefficient will be seen from FIG. 6 where it is obvious that the filling coefficient is greater than that shown in the conventional fabric of FIG. 5. Consequently, the F necessary to pull out a fiber from its bundle (FIG. 6), is considerably higher that the force F, (FIG. In the fabric of the present invention, the coefficient m is at least 0.4 and often F is so high as to approach or exceed its strength of the fiber itself. This results in considerable lowering of deformation due to the crosswise stressing of the fabric and in an important increase of fabric strength in its transverse direction.

As an example of the versatility of the present invention, reference is made to FIG. 7 showing a quilted fabric of layered material reinforced by one warp end system in chain stitch construction. The fabric has a fibrous web 4 comprising a plurality of layers 5 all having fibers transversely arranged relative to the axis of the fabric. The web 4 is reinforced by parallel rows of interconnected face loops 6 and back loops 7 arranged in chain stitched wales 8. For the purpose of example, a setting of 40 wales for each It) cm with I00 courses per [0 cm length was employed. The back loop 7 penetrates through the web 4 from the binding point A which, as will be seen, lies substantially at the front face of the fabric. Because of the tension placed on the reinforcing thread, its front loop 6 tends to indent the fabric creating something of a valley between two adjacent hills or mounds 9 centrally between the adjacent wales 8. As a result a quilted fabric having a ribbed or corduroy appearing surface along the successive mounds 9 is formed. The back or reverse face is similarly formed. It will be appreciated that when a greater number of courses are employed the shape of the faces will be closer to those shown in FIGS. 3, 4 and 6.

Another variation is shown in FIG. 8. This fabric is similar to that shown in FIG. 7, except that the reinforcing thread is made into a network of combined chain stitches and tricot stitches. In FIG. 8, the tricot stitch is indicated by dot and dash line 10 which forms a portion of the stitch structure on its back face. Thus, the tricot thread leaves back loop of wale 8 after it penetrates the web 4 and passes over to the adjacent wale 8' where it interlaces with the thread of that Wale to form the loop 6' of the next course. In the next stitch, the tricot thread forms the back loop 10' and returns to its initial wale 8 where it subsequently forms the loop 6" of the third or next succeeding course. The back loops 7 of the simple chain stitch interlace as they did in the construction of FIG. 7.

The combined chain and tricot stitch construction of FIG. 8 changes the fabric in that the corduroy or ribbed effect on its reverse face is suppressed, while the front face remains the same. The fabric thus produced has a corduroy effect on one side and a smooth effect on the reverse side. Since two warp systems are used to form the network. this reinforced thread is stronger and the tendency for the fabric to unravel is reduced. The fabric also has a stronger tensile strength since the tricot thread passes to and fro between adjacent wales.

The quilted fabrics, according to this invention, may be produced on any conventional quilting machines. One such machine being described in full in the aforementioned patent US. Pat. No. 3,3l0,964. These machines may be one or multibar flat warp knitting machines equipped with compound or two-part needles provided with piercing points and the books of which are provided with latches slidably mounted within the needle stems. The needles and the latches are mounted in needle and latch bars, respectively, which are driven in usual manner from a common drive shaft. The needles cooperate with lapping guide units which are fitted with lapping guides mounted on guide bars moving transversely in holders which, similarly as the needles and latches, are driven from the main drive shaft. Operation of this machine proceeds in the conventional manner. A quilting machine, however, unlike the conventional warp knitting machine, guides the fibrous web on a stationary knockover table and amovable web holder table, which motion carries the web. The web holder table is movable from the main shaft.

The quilting machine is further equipped with a conveyor means for supplying the fibrous web to the knitting mechanism between the knock-over and web holder tables. Warp beams are arranged on the machine in a known manner for feeding and unwinding the binding thread. The take-up means selvedge trimmers, etc. are also supplied. The fibrous web may be prepared on a web forming machine of the cotton, wool or flax types, and it is superimposed in layers on any known web-laying equipment, such as the Blamier's lap forming apparatus, to obtain the required thickness or weight.

In the production of a quilted fabric according to the invention (FIGS. 9a 9c) the conveyor system 13 carries the fibrous web 4 between the stationary knockover table 11 and the web holder table 12 to cross the path of the needles 14. The needles l4 reciprocate from their rear position forward, they pass between the two tables ll, 12, penetrating at the same time the fibrous web 4 which is held by the web holder table 12. The needles 14 complete their movement to their rearmost position where the binding threads 15, 15 are lapped on their hooks by the lapping guides 16, 16' (FIG. 9b). The needles 14 then return, their hooks being colsed by the sliding latches 17, and pull the loops formed of the binding warp ends l5, 15 through the fibrous web 4 and the previously formed loops (FIG. Thus, new loops are formed and the old loops are knocked over the heads of the needles 14 as they return to their rear position. As soon as the needles 14 have returned, the produced fabric length is drawn off. The fabric length to be drawn off depends on the given number of courses in the fabric.

The stitch construction in our case a two-bar construction is preset by adjusting the movement of the lapping guides l6, 16' in the manner known with conventional warp knitting machines, and by threading these lapping guides.

It will be obvious from the foregoing that among the novel features of the present invention is the use of a substantially increased number of courses per unit length, increased tension of the thread itself, a new shape to the loop structure and the maintenance of the binding point, or knock-over point at or substantially near one of the faces of the fabric. It is these factors which individually and jointly provide one or more of the advantages enumerated above and provide fabrics which are stronger, more durable, more attractive and of wider use than heretofore. With this in mind, it will be appreciated that the invention may be employed to provide a variety of differently appearing quilted fabrics and with a variety of different materials.

Any stitch structure or network may be employed in Wale set: 60 per cm Course set: N 137.1 per 10 cm Suitable end uses: childrens wear, coats and overcoats, industrial fabrics EXAMPLE 3 Fibrous web of wool fibers addition to the simple chain and tricot stitches shown, 10 Specific weight 7 weight G 300 glsqlm as for example double tricot, double sateen. in the sim- Twobar Stitch construction Chain Stitch mam plest quilted fabrics, a single warp, simple chain stitch Binding thread: exturizgd polyester filamem yam T construction may be used to reinforce the fibrous web 120 den on both bars lengthwise while the laying of the fibers crosswise in the w ls Set 50 er 10 cm web may be relied upon for transverse stability. This C a p ourse set: N g 92.9 per 10 cm type of quilted fabric can be used mainly for insulation purposes where the strain may be exposed to is not con- 0.4 a ()2 B 194 siderable. if some additional transverse strength is required, the web may be reinforced in either tricot or sa- Sultable end uses Blankets winter coats teen stitch constructions or double warp stitch con- EXAMPLE 4 struction. With a double warp stitch construction, neither unravelling nor loosening of the fibrous web can of 5605c Staple'an cotton was: OCCUL Specific weight: y 1.53, weight G 400 g/sq.m

The fibrous web may be made of monofilamem Binding thread: cotton ply yarn Nm 85/2 (T= 21 L76 brilated or other forms of natural, man-made, or inor- 25 (16) ganic fibers, or blends thereof. It is also possible to use Onc'bar glitch Construction chain Smch a sandwich web comprising different materials and the Wale Set: 40 P 10 Cm web may be of isotropic anisotropic character. The fi- Course I! N 2 1.7 per 10 cm bers should as a rule, however, be arranged crosswise in the fabric as noted above. The weight of the fibrous (m a B 1007) w b may be less th 50 g/5q,m lth u h it ma be f u Suitable end uses: Packaging materials, industrial to twelve times higher if desired. The type of fibers or fabrics their blends or the sandwich combinations may be chosen to suit the required wear properties or end uses EXAMPLE 5 of the finished product. The binding thread may be ei- Fibrous web of viscose/polypropylene staple blend, ther a spun yarn, single or plied, a monofilamentary or two colors (the upper face layer in one color. the lower plied filament yarn, both natural or man-made. For the ba k l r i th oth l i h G 300 g/sqm most part, cotton, viscose, wool or blended fibrous S ifi weight 152 095/; 1 235 webs should reinforce Ol' Stitch-bond polyamide, 40 Tw0 bar stitch onstruction sateen sateen oppopolyester or viscose filament yarn warps. Site As examples of the versatility of the present inven- Binding thread. polyamide filament yam den tion, there follows a number of examples (for illustraon both bars tion only) wherein the present invention is employed to Wale set: 60 per 10 cm provide improved fabrics. The execution of each exam COWSe Set: N g 889 per 10 cm ple was performed on conventional equipment and in accordance with the concepts taught herein and the re- (m 0.4, a 0.2, B 28.45) sultant fabric was tested for each of the suggested end Suitable end uses: bedspreads, blankets uses.

EXAMPLE 1 EXAMPLE 6 Fibrous web of 2.5 den., mm viscose staple Two ,componem fibrous w eb: non'shrmk (wool) in the upper layer, shrink material (Rhovyl) in Specific weight 7' 1.52, weight G g/sq.m Two-bar stitch construction tricot tricot, opposite the lower mm] welght G 240 g/sq'm pp g Specific weight: y L36 1.40/2 1.38 Binding thread: Viscose filament yarn T=60 den., on 55 p i stitch construcflon cham Stnch both bars Binding thread: polyamide filament yarn T= 9O den.

Wale Per 10 Cm Wale set: 30 per 10 cm Course set: N a 239.5 per 10 cm Course Set: N Z P Cm (filling coefficient m 0.4, a d), B 11.44) 60 (m 0.4 a 0.08 B 24]) Suitable end uses: print backings, shirtings EXAMPLE 2 Fibrous web of cotton fibers Specific weight y 1.55, weight G 150 g/sq.m

Suitable end uses: Corduroy or twill backed cloth simulation EXAMPLE 7 Two-bar stitch construction chain stitch tricot Binding thread: polyamide filament yarn T den. on both bars Fibrous web cotton fibers Specific weight: y L55, weight G 350 g/sq.m Binding thread: texturized polyester filament yarn mum" .w-uu-wmnww w... 4 r... .r r

T 250 den. for the plain stitch construktion; polyamide yarn T 90 den. for the chain stitch construction Resultant denier T V 250 WW2 160 den.

Wale set: 50 per l cm Course set: N 5 97.3 per cm where B is determined by the equation 2.88 (i 8 I"n|"y(().483 or) wherein G specific weight in g/sq.m of the fibrous web to be processed binding thread titre in denier y= specific gravity in g/cu.cm of the fibers in the web m=the filling coefficient constant defined as the ratio between the sum of fiber cross section areas in a stitch loop and the total area confined by the stitch loop equalling 0.40

a the constant relating to machine operation a fibrous web weight of up to 200 g/sq.m a equals zero while with a fibrous web of weight in the range of 200 to 600 g/sq.m, a is determined by the equation or 0.002 G 0.400.

2. The fabric according to claim 1 wherein said courses are not less than 80 per l0 cm.

3. The fabric according to claim 1 wherein said knit system comprises a chain stitch having a front loop formed of a double thread and a back loop formed of a single thread.

4. The fabric according to claim 3 wherein said wales are arranged in parallel with each other and binding points form each course and are arranged in parallel rows transversely to said wales.

5. The fabric according to claim 3 wherein said knit system is a combination of chain and tricot stitch, having said front loop formed with two threads, and said back loop formed with one thread, the interconnecting thread between tricot stitches being formed with the back loops.

6. The fabric according to claim 1 having front and back loops in said warp knit system which are interconnected in a series of binding points. the binding points of said front and back loops being located along a plane substantially parallel to and adjacent to one face of said fabric.

7. The fabric according to claim 6 wherein the cross sectional area of the fabric above said plane is substantially smaller than the cross sectional area below said plane.

8. In the method of forming a quilted fabric having a fibrous web fill reinforced with network of warp threads knitted in a plurality of wales and courses having a front and back loops interconnected in a series of binding points, the improvement comprising the step of forming the fabric with the number of courses is at least equal to N, N being defined by the equation where B is determined by the equation 2.88 c; B m

wherein G specific weight in g/sq.m of the fibrous web to be processed T binding thread titre in denier 'y= specific gravity in g/cu.cm of the fibers in the web m the filling coefficient constant defined as the ratio between the sum of fiber cross section areas in a stitch loop and the total area confined by the stitch loop equalling 0.40 a the constant which with the fibrous web weight up to 200 g/sq.m 0: equals zero while the fibrous webs of weight range of from 200 to 600 g/sq.m a is determined by the equation 9. The method according to claim 8 including the step of tensioning the warp threads to a predetermined level whereby the binding points between front and back loops is formed in a plane parallel to and substantially at one face of the fabric.

10. The method according to claim 8 wherein the number of courses stitches is not less than per 10 l ll 

1. A quilted fabric comprising a fibrous web fill and a reinforcing thread network applied in a warp knit system having a plurality of wales and courses, wherein the number of courses per 10 cm being at least equal N, N being determined by the equation
 2. The fabric according to claim 1 wherein said courses are not less than 80 per 10 cm.
 3. The fabric according to claim 1 wherein said knit system comprises a chain stitch having a front loop formed of a double thread and a back loop formed of a single thread.
 4. The fabric according to claim 3 wherein said wales are arranged in parallel with each other and binding points form each course and are arranged in parallel rows transversely to said wales.
 5. The fabric according to claim 3 wherein said knit system is a combination of chain and tricot stitch, having said front loop formed with two threads, and said back loop formed with one thread, the interconnecting thread between tricot stitches being formed with the back loops.
 6. The fabric according to claim 1 having front and back loops in said warp knit system which are interconnected in a series of binding points, the binding points of said front and back loops being located along a plane substantially parallel to and adjacent to one face of said fabric.
 7. The fabric according to claim 6 wherein the cross sectional area of the fabric above said plane is substantially smaller than the cross sectional area below said plane.
 8. In the method of forming a quilted fabric having a fibrous web fill reinforced with network of warp threads knitted in a plurality of wales and courses having a front and back loops interconnected in a series of binding points, the improvement comprising the step of forming the fabric with the number of courses is at least equal to N, N being defined by the equation
 9. The method according to claim 8 including the step of tensioning the warp threads to a predetermined level whereby the binding points between front and back loops is formed in a plane parallel to and substantially at one face of the fabric.
 10. The method according to claim 8 wherein the number of courses stitches is not less than 80 per 10 cm. 